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(No IKodel.)

A. SCHNELLBR 8D W. J. WISSB.

METHOD 0F INSULATING HIGH TENSION GOILS 0F TRANSFORMHRS.

No. 536,319. Patented Mar. 26, 1895.

UNITED STATES PATENT OEEICE.

AUGUST SCHNELLER, OF AARLANDERVEEN-ALFEN, AND VILLEM JOHN VISSE, OF HAARLEM, ASSIGNORS TO HENRY TINDAL, OF AMSTERDAM NETHERLANDS.

METHOD 0F INSULATING HIGH-TENSION COILS 0F TRANSFORMERS.

SPECIFICATION forming part of Letters Patent No. 536,319, dated March 26, 1895.

Application tiled December 27, 1894l Serial No. 533.142. (No model.) Patented in France January 22,1894, No. 285.686; in Switzerland January 27, 1894, No. 8.113; in Belgium ,Tanuary 27, 1894,1T0. 108,300; in Luxemburg January 29,1894,No. 1,967; in Sweden February 8, 1894, No. 5.400; in Italy February 9, 1894, No. 35,719; in Austria February 10, 1894, XLIV, No. 76; in Hungary February 16,1894,No.`55: in Spain March 1, 1894l No. 15,427, and in EnglandMarch 17,1894,No 5,647.

To all whom it may concern:

Be it known that we, AUGUST SCHNELLEE, a resident of Aarlanderveen-Alfen, near Leyden, and WILLEM JOHN WIssE, a resident of Haarlem, Netherlands, both subjects of the Queen of Holland, haveinvented an Improved Method of Insulating the Secondary Coils of Electrical Transformers for High -Tension Currents, (for which patents have been obtained in the following countries: France, No. 235,686, dated January 22,1894; Switzerland (prov.,) No. 8,113, dated January 27, 1894; Belgium, No. 108,300, dated January 27, 1894; Luxemburg, No. 1,967, dated January 29,1894; Sweden, No. 5,400, dated February 8, 1894; Italy, No. 35,719, dated February 9, 1894; Austria, No. 7 6, Vol. XLIV, dated February 10, 1894; Hungary, No. 55, dated February 16, 1894; Great Britain, No. 5,647, dated March 17, 1894, and Spain, No. 15,427, dated March 1, 1894, all of these patents being granted to Baron Henry Tindal, of Amsterdam, in the Kingdom of Holland,) of which the following is an exact specification.

This invention has reference to improvements in the manufacture of secondary coils for transformers designed to transform electric currents of low tension into electric currents of high tension, say for example thirty thousand volts and upward, for which purpose it is requisite that the insulation at all parts of the coil should be compact or dense, that is to say, without interstices, and perfectly dry.

Referring to the accompanying drawings, in which similar letters denote similar parts throughout both views: Figure 1 illustrates a sector-like piece supposed to be cut out of a secondary transformer-ring or coil constructed according to this invention, and Fig. 2 represents to a larger scale a part in cross-section of such ring or coil.

The secondary ring or coil is constructed as follows: Copper-wire a covered with say four layers of insulating material b, it may be with layers of silk, cotton, or tape applied to the wire in the ordinary manner, is wound helically in such a manner as to produce a ring or coil (hereinafter called a coil) preferably of rectangular form in cross section. Between the several adjacent layers of wire a, thin layers c of insulating material, such as paper, cotton, dro, shown only in Fig. 2, are inserted during the winding, and at greater distances apart there are inserted thicker layers c of paper, cotton, duc., so that the layers of wire are completely separated one from the other. The several layers of wire and insulating material c c composing the coil are tied or fastened securely together by binding cords d passed several times transversely through the coil as shown in Fig. 1. The coil thus formed is then boiled in wax or a waxy substance, by preference in bees wax or ceresine with colophony, for say twelve hours after which it is dried by pressure. The coil is then put into position for use as a secondary coil in a transformer, and an electric current of the same strength as that intended to be finally used in practice is passed through the primary coil ot' the transformer, whereby the secondary coil eltects the conversion of the main current into a secondary current of high tension. By this means the coil will be heated and the wax or waxy substance therein remelted, the coil being left in operation until the last trace of moisture has been removed. During this operation a further quantity of wax or waxy substance is added to the coil, it may be by means of a brush. When, finally, the coil is no longer warm due to the gradual filling up of the interstices in the coil with wax, and to the removal of moisture, it is given a coat of paint and then a coat or layer of protecting material such as shellac varnish.

As will be obvious, the main object of the invention is to remove every trace of moistd ure from the coils, and to avoid the presence of any spaces or cavities, however small, in the insulating material. Only in this manner can short circuiting and heating be avoided.

By the preliminary working of the transformer, moisture, always present in the coil after the same has been boiled and pressed, is veectually removed, and the interstices in the coil effectually filled up, since, as is evident Where there are spaces and moisture, shortcircuiting and heating of the coil very readily take place, so that evaporation of the moisture and the melting together of the wax or waxy substance precisely at these places is the necessary consequence. Furthermore, the addition of wax, or of a waxy substance by painting or otherwise, which is continuously carried on during the heating operation, alwaysY provides sufficient wax or waxy substance to take the place of that absorbed by the filling up of the interstices in the coil, and also provides for the filling up of any fresh interstices produced by the evaporation of the moisture.

By constructing secondary coils in the manner described, that is to say, by using insulated wire, dividing the convolutions thereof by layers of insulating` material, such as paper, cotton and thelike, intimately connecting the convolutions by boiling in wax or a waxy substance, and pressing, and protecting, the treated coil by outer coatings of paint and varnish or shellac there is produced a coil which,withoutbecoming in the least hot when in use will safely withstand tensions of thirty thousand volts and upward.

Having thus fully described the nature of this invention and in what manner the saine is to be performed, whatwe desire to secure by Letters Patent of the United States is- 1. The manufacture of secondary transformer coils for use in the production of high tension electric currents, by boiling coils of insulated wire in wax or a waxy substance, then pressing them, and then putting them into preliminary use for the purpose of evaporating moisture there from and of filling up the interstices therein, additional wax or waxy substance being supplied to the'coils as long as heating thereof is produced by the passage of an electric current therethrough, as set forth.

2. A secondary coil for a transformer, composed of wire covered with several layers of insulating material, and the convolutions of which are embedded in wax or a waxy substance, and are separated from one another in a circular direction by strips or layers c-c of insulating material, such as paper, cotton and the like, and are firmly secured together by binding` cords passed several times transversely through the coil, which is iinally provided with au outer protecting layer of material such as shellae-varnish, as set forth.

in testimony whereof we have signed this specification in the presence of two subscribing witnesses.

AUGUST SCHNELLER. WILLEM JOHN WISSE. lVitnesses:

ARTHUR ALBERT S'roKns, AUGUST SIEGFRIED DoonN. 

